General Chemistry

the Central Science Brown & LeMay

Chapter One: Introduction, Matter & Measurement

General Chemistry

the Central Science Brown & LeMay

Chapter One: Introduction, Matter & Measurement

Molecular Perspective Classifications of Matter

States, Pure Substances, Mixtures, Elements, Compounds

Properties of Matter Units of Measurement SI Units, Derived Units, Uncertainty, Dimensional Analysis

Atoms & Molecules -- basic nature of chemistry

-necessary to understand the nature of matterart, medicine, agriculture, environment, home

Classifications of Matter-states gas, liquid, solid (H)-pure substance fixed composition/distinct properties

(elements or compounds)-elements cannot be decomposed to simpler

substances-compounds combination of two or more elements -mixture combination of two or more pure substances

(heterogeneous & homogeneous/solutions)

Gas Liquid Solid Gas Liquid Solidno shape, no volume

volumeno shape

volume &shape

Elements-112 elements known-listed on periodic table with symbols (H)-arranged in a particular order such that

closely related elements are grouped Compounds

-two or more elements chemically combined-law of constant composition or definite

proportions eg. water is always 11% H and 89% O

while peroxide is 6% H and 94% O

Gold Au Aurum Latin, AuroraGoddess of dawn

Mercury Hg Hydrargyrum Greek,hydroargyro,water seeker

Helium He Helios Greek, sun

Beryllium Be Beryllos Greek, preciousstone beryl

Sodium Na Natrium Latin, name f oralkaline subs.

Chromium Cr Khroma Greek, color

MixturePhysical combination of two or more pure substanceswhich can be physically separated into the components

Heterogeneous-composition, properties, appearance vary

-non-uniform in appearance

Homogeneous-uniform appearance/properties but may vary between different samples-a “solution”

HeterogeneousMixture

Element Compound

Can it be decom posedChem ically?

Pure Substance HomogeneousMixture

(solution)

Can it be separatedPhysically?

HomogeneousMixture

Is it uniformthroughout?

Matter

no yes

yesno

no yes

Properties of Matter-Physical Properties -- color, odor, density, b.pt.

-Chemical Properties -- chemical changes occur

-Intensive Properties -- do not depend upon quantity of material present temp, m.pt., density

-Extensive Properties -- dependent upon the quantity of material present mass, volume

Changes of Matter-Physical -- appearance changes but not

composition

-Chemical -- transformation into chemically different substance

Observations & Experiments

Find Patterns, Trends,

Laws

Formulate & Test

Hypothesis

Theory

Scientific Method

Units of MeasurementSI Units

Quantity Name Abbrev.

Mass* Kilogram kgLength Meter mTime Second sElectric Curr. AmpereATemperature Kelvin KLum. Intensity CandelacdAmount Molemol

*quantity of matter

Selected Prefixes

Prefix Abbrev. Meaning

Mega- M 106

Kilo- k 103 Deci- d 10-1

Centi- c 10-2 Milli- m 10-3 Micro- 10-6 Nano- n 10-9 Pico- p 10-12 Femto- f 10-15

Temperature

273K 0 C 32 F

373K 100 C 212 F

Kelvin Celsius Fahrenheit

Derived Units -- combinations of other units

Volume-SI unit for volume is m3 -1 L = 1 dm3

-1 mL = 1cm3

Density-amount of mass in a unit volume-combination of mass and volume units-typically g/mL for solids and liquids & g/L for gases

Practice Exercise 1.3 (pg. 18)

15.0 g of ethanol needed, density = 0.789 g/mL, how many mL of ethanol needed?

need a volume unit, mL, we have a mass unit, g, and a combination unit, g/mL

15.0 g x 1 mL =

0.789 g

19.0 mL

(19.0110)

Uncertainty in MeasurementPrecision vs Accuracy

-Precision -- agreement of measurements-Accuracy -- proximity to true value

good precision poor precision good precisiongood accuracy poor accuracy poor accuracy

1 2 3

2.55

2.5

1 2 3

Significant Figures1. all non-zero digits are significant 1.2357

2. zeros between non-zero digits are significant1.20054

3. zeros to the left of the first non-zero digit in a number are not significant 0.0023

4. when a number ends in zeros to the right of decimal point, the zeros are significant 1.2300

5. when a number ends in zeros which are to the left of the decimal those zeros may or may not be significant 2000 or 2000 or 2000 or 2000

Use in Calculationsmultiplication & division

-result reported to no more total sig. digits than

the piece of data with the least number of digits

addition & subtraction-result reported to same number of significant decimal places as the piece of data with the least number of significant decimal places

Use in Calculationsmultiplication & division

-result reported to no more total sig. digits than

the piece of data with the least number of digits

(1.27)(2.3) = 2.921 2.9

addition & subtraction-result reported to same number of significant decimal places as the piece of data with the least number of significant decimal places

1.0 + 2.15 + 3.468 = 6.6186.6

Dimensional Analysis

1 ft = 12 in

1 ft = 12 in 1 ft 1 ft 1 = 12 in or 1 = 1 ft 1 ft 12 in conversion factors

conversion factors convert between two different units

Convert 56 inches to feet.

56 in x 1 ft = 12 in

4.7 ft

Practice Excersize 1.8 pg 26

Convert 500.0 mi to km

1. need a conversion factor 1 mi = 1.6093 km

2. set up to cancel mi 500.0 mi x 1.6093 km

1 mi3. do the math, cancel the appropriate units

500.0 mi x 1.6093 km = 804.6 km

1 mi

Convert the volume of a 10 m x 10 m x 10 m room to liters.

1000 m3 x ? 1 dm3 = 1 L 1 dm = 0.10 m

1000 m3 x 1 dm x 1 dm x 1 dm = 1.0 x 106 dm3

0.10 m 0.10 m 0.10 m 1 dm3 0.0010 m3

1.0 x 106 dm3 x 1 L = 1.0 x 106 L 1 dm3

Problems

If I weigh 52.3 kg, how many grams do I weigh?

If a tennis ball is served at 140 mph, what is its speed in m/s?

You have a 40 lb baggage limit, the scale reads 17.97 kg. Are you over or under?

Convert 2.5 L to cm3

Problems

Glycerol is a viscous, sweet-tasting liquid. In an experiment, a 25.0 mL sample was found to weigh 31.6 g. What is the density of glycerol?(2.60)

Diethyl ether has a density of 0.713 g/mL. What volume of diethyl ether is needed to equal 28.0 g?(2.64)

Problems

The density of the sulfuric acid solution of a fully charged lead storage battery is about 1.28 g/mL. What is the mass of the solution whose volume is 1.50 L? (2.89)

The density of red blood cells is about 1.093 g/cm3, somewhat higher than that of blood plasma. What is the mass of cells whose volume is 5.67 cm3?(2.88)

Problems To identify a metal, an experimenter

placed a 32.6 g sample in a grad. cylinder. He then poured in 25.0 mL of water, covering the metal and bringing the liquid level in the cyliner to 28.7 mL. What is the density of the metal? (2.62)

You are buying carpet @ $15.00/sq. yd for a 1500 sq. ft house. How much will it cost?

Problems If liquid nitrogen has a boiling point of

77K, and the temperature is -300°F, will it be a solid, liquid or gas?

A 175 lb patient is to undergo surgery and will be given an anesthetic intravenously. The safe dosage of anesthetic is 12 mg/kg of body weight. Determine the maximum dose of anesthetic that should be used.